My ex-husband was a bibliophile whose most bitter memory of our marriage was any book I ever made him get rid of. Which I did because he was in the military, so we moved a lot and had weight limits and sometimes had DUPLICATES of books, like the illustrated and unillustrated version.
THAT was his zinger during our divorce: He regretted every single book I ever made him get rid of!!!!!! GRRR!!!!
He also had extremely serious eyesight problems. Between the two, I picked up seemingly obscure information about physical books that most people seem to have never heard.
Prepping A Large Hardback
I've never seen or heard this from anyone else, but he prepped new books for reading to protect the spine. Especially large hardbacks because they are prone to breaking when you hold them open a long time at the same spot.
So before anyone was allowed to read a new book in the house, he went through a process of opening the book in several different places and applying enough pressure to break in the spine and foster bending without breaking.
Ownership Templates
If you lend books out, you can buy fancy little stickers to place inside the cover that says something like "This book belongs to _________" and write your name in it.
Magnifiers
We had multiple magnifiers in various shapes, sizes and designs. Magnifiers seem to be the top hit if you search for "reading tools" and are probably the least obscure item on this list.
Book Covers
You can buy or make book covers for hardback books to help preserve the book from wear and tear or pretty up a badly worn book whose cover has seen better days.
Bookmarks
We had cups full of bookmarks sitting on our endless bookshelves, many of which were gifts from one of us to the other with inspirational sayings. Most were inexpensive cardboard bought for a dollar with a tassel. Some were metal or engraved leather.
Book Darts
My ex had a book dart addiction. I could buy him like five hundred and -- slurp -- they were GONE and he couldn't spare one or two for me a few days later.
These are tiny metal bookmarks designed to place on the edge of a page and physically point to a specific line.
Dog earring a book was a hanging offense in his mind, but he liked keeping track of his favorite quotes in his favorite books and book darts were how he did it.
Book Weights or Page Holders
He had what looked a bit like a flat dumbbell for holding a book open. If you search online for book page holders, you will see other options for physically holding a book open on your desk or at a podium so your hands are free.
Homemade Tool for Early Readers
This doesn't come from my ex. I cannot readily find it, so may no longer have it, but on my original homeschooling site I had a printable template emailed me by someone I knew through a gifted homeschooling list.
Children who become voracious readers at a young age frequently find it frustrating and exhausting because their eyes aren't developmentally ready. They have trouble tracking. In other words, they have trouble following the same line in a wall of text.
Take something stiff like lightweight cardboard. Use something like a manila folder or index card or the cardboard back from a legal pad.
Measure the width and height of one or two lines of text for the book in question.
Draw a rectangle on the cardboard in those parameters and cut it out.
This tool covers up most parts of the page you aren't reading and shows only one or two lines at a time so it's easier for a young reader to keep track of where they are.
I was sent a template for a tool with a handle. But I never used this and I haven't seen a commercial version, so I'm guessing there's a lot of room for playing with the design to figure out what works best.
Play around until you have a piece of cardboard with a cut out your CHILD is comfortable handling.